scholarly journals Observations of The Lower-Tropospheric Temperature Profiles Using Three Wavelength CO2-DIAL

2020 ◽  
Vol 237 ◽  
pp. 03021
Author(s):  
Yasukuni Shibata ◽  
Nagasawa Chikao ◽  
Makoto Abo
Keyword(s):  
Boundary Layer ◽  
Temperature Profile ◽  
Nd:Yag Laser ◽  
Lower Troposphere ◽  
Temperature Inversion ◽  
Temperature Profiles ◽  
Tropospheric Temperature ◽  
Differential Absorption ◽  
Temperature Profiler ◽  
Continuous Temperature

The eye-safe lower-tropospheric temperature profiler with three wavelength differential absorption lidar (DIAL) technique which can perform the continuous temperature profile observation through daytime and nighttime is conducted. The DIAL consists of a Nd:YAG laser pumped an OPG tuned around 1573 nm of an CO2 absorption line with 2 mJ/pulse at 400 Hz repetition rate and a receiving telescope of 25cm diameter. In this paper, we show the result of continuous temperature profile observations over 25 hours from 0.39 to 2.5 km altitude in the lower-troposphere. We can see temporally the generation and disappearance of the temperature inversion layers in the planetary boundary layer.

scholarly journals Methodology for determining multilayered temperature inversions

2015 ◽  
Vol 8 (5) ◽  
pp. 2051-2060 ◽  
Author(s):  
G. J. Fochesatto
Keyword(s):  
Temperature Profile ◽  
Large Scale ◽  
Error Function ◽  
Inversion Layer ◽  
Lower Troposphere ◽  
Temperature Inversion ◽  
Linear Interpolation ◽  
Pollution Dispersion ◽  
Thermal Inversion ◽  
Temperature Inversions

Abstract. Temperature sounding of the atmospheric boundary layer (ABL) and lower troposphere exhibits multilayered temperature inversions specially in high latitudes during extreme winters. These temperature inversion layers are originated based on the combined forcing of local- and large-scale synoptic meteorology. At the local scale, the thermal inversion layer forms near the surface and plays a central role in controlling the surface radiative cooling and air pollution dispersion; however, depending upon the large-scale synoptic meteorological forcing, an upper level thermal inversion can also exist topping the local ABL. In this article a numerical methodology is reported to determine thermal inversion layers present in a given temperature profile and deduce some of their thermodynamic properties. The algorithm extracts from the temperature profile the most important temperature variations defining thermal inversion layers. This is accomplished by a linear interpolation function of variable length that minimizes an error function. The algorithm functionality is demonstrated on actual radiosonde profiles to deduce the multilayered temperature inversion structure with an error fraction set independently.

scholarly journals The effect of cloud liquid water on tropospheric temperature retrievals from microwave measurements

2017 ◽  
Author(s):  
Leonie Bernet ◽  
Francisco Navas-Guzmàn ◽  
Niklaus Kämpfer
Keyword(s):  
Temperature Profile ◽  
Liquid Water ◽  
Cloud Model ◽  
Cloud Base ◽  
Spectral Information ◽  
High Temporal Resolution ◽  
Temperature Profiles ◽  
Tropospheric Temperature ◽  
Cloud Liquid Water ◽  
Cloud Models

Abstract. Microwave radiometry is a suitable technique to measure atmospheric temperature profiles with high temporal resolution during clear sky and cloudy conditions. In this study, we included cloud models in the inversion algorithm of the microwave radiometer TEMPERA (TEMPErature RAdiometer) to determine the effect of cloud liquid water on the temperature retrievals. The cloud models were built based on measurements of cloud base altitude and integrated liquid water (ILW), all performed at the aerological station (MeteoSwiss) in Payerne (Switzerland). Cloud base altitudes were detected using ceilometer measurements while the ILW was measured by a HATPRO (Humidity And Temperature PROfiler) radiometer. To assess the quality of the TEMPERA retrieval when clouds were considered, the resulting temperature profiles were compared to two years of radiosonde measurements. The TEMPERA instrument measures radiation at 12 channels in the frequency range from 51 to 57 GHz, corresponding to the left wing of the oxygen emission line complex. When the full spectral information with all the 12 frequency channels was used, we found a marked improvement in the temperature retrievals after including a cloud model. The chosen cloud model influenced the resulting temperature profile, especially for high clouds and clouds with a large amount of liquid water. Using all 12 channels however presented large deviations between different cases, suggesting that additional uncertainties exist in the lower, more transparent channels. Using less spectral information with the higher, more opaque channels only also improved the temperature profiles when clouds where included, but the influence of the chosen cloud model was less important. We conclude that tropospheric temperature profiles can be optimized by considering clouds in the microwave retrieval, and that the choice of the cloud model has a direct impact on the resulting temperature profile.

scholarly journals Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height

2011 ◽  
Vol 4 (2) ◽  
pp. 143-149 ◽  
Author(s):  
C. A. Keller ◽  
H. Huwald ◽  
M. K. Vollmer ◽  
A. Wenger ◽  
M. Hill ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Fiber Optic ◽  
Temperature Inversion ◽  
Nocturnal Boundary Layer ◽  
Temperature Sensing ◽  
Temperature Profiles ◽  
Distributed Temperature Sensing ◽  
Boundary Layer Height

Abstract. A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS) with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH) was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement with the MH derived from concurrent Radon-222 (222Rn) measurements and in previous studies.

scholarly journals Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height

2010 ◽  
Vol 3 (3) ◽  
pp. 2723-2741 ◽  
Author(s):  
C. A. Keller ◽  
H. Huwald ◽  
M. K. Vollmer ◽  
A. Wenger ◽  
M. Hill ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Fiber Optic ◽  
Temperature Inversion ◽  
Nocturnal Boundary Layer ◽  
Temperature Sensing ◽  
Temperature Profiles ◽  
Distributed Temperature Sensing ◽  
Boundary Layer Height

Abstract. A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS) with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH) was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement to the MH derived from concurrent Radon-222 (222Rn) measurements and in previous studies.

scholarly journals The effect of cloud liquid water on tropospheric temperature retrievals from microwave measurements

2017 ◽  
Vol 10 (11) ◽  
pp. 4421-4437 ◽  
Author(s):  
Leonie Bernet ◽  
Francisco Navas-Guzmán ◽  
Niklaus Kämpfer
Keyword(s):  
Temperature Profile ◽  
Liquid Water ◽  
Cloud Model ◽  
Cloud Base ◽  
Spectral Information ◽  
High Temporal Resolution ◽  
Temperature Profiles ◽  
Tropospheric Temperature ◽  
Cloud Liquid Water ◽  
Cloud Models

Abstract. Microwave radiometry is a suitable technique to measure atmospheric temperature profiles with high temporal resolution during clear sky and cloudy conditions. In this study, we included cloud models in the inversion algorithm of the microwave radiometer TEMPERA (TEMPErature RAdiometer) to determine the effect of cloud liquid water on the temperature retrievals. The cloud models were built based on measurements of cloud base altitude and integrated liquid water (ILW), all performed at the aerological station (MeteoSwiss) in Payerne (Switzerland). Cloud base altitudes were detected using ceilometer measurements while the ILW was measured by a HATPRO (Humidity And Temperature PROfiler) radiometer. To assess the quality of the TEMPERA retrieval when clouds were considered, the resulting temperature profiles were compared to 2 years of radiosonde measurements. The TEMPERA instrument measures radiation at 12 channels in the frequency range from 51 to 57 GHz, corresponding to the left wing of the oxygen emission line complex. When the full spectral information with all the 12 frequency channels was used, we found a marked improvement in the temperature retrievals after including a cloud model. The chosen cloud model influenced the resulting temperature profile, especially for high clouds and clouds with a large amount of liquid water. Using all 12 channels, however, presented large deviations between different cases, suggesting that additional uncertainties exist in the lower, more transparent channels. Using less spectral information with the higher, more opaque channels only also improved the temperature profiles when clouds where included, but the influence of the chosen cloud model was less important. We conclude that tropospheric temperature profiles can be optimized by considering clouds in the microwave retrieval, and that the choice of the cloud model has a direct impact on the resulting temperature profile.

scholarly journals Profiling of CH<sub>4</sub> background mixing ratio in the lower troposphere with Raman lidar: a feasibility experiment

2018 ◽  
Author(s):  
Igor Veselovskii ◽  
Philippe Goloub ◽  
Qiaoyun Hu ◽  
Thierry Podvin ◽  
David N. Whiteman ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Elastic Scattering ◽  
Nd:Yag Laser ◽  
Counting Rate ◽  
Photon Counting ◽  
Lower Troposphere ◽  
Free Troposphere ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Additional Control

Abstract. We present the results of methane profiling in the lower troposphere using LILAS Raman lidar from Lille University observatory platform (France). The lidar is based on a tripled Nd:YAG laser and nighttime profiling up to 4000 m with 100 m height resolution is possible for methane. Agreement between measured the photon counting rate in the CH4 Raman channel in the free troposphere and numerical simulations for a typical CH4 background mixing ratio (2 ppm) confirms that CH4 Raman scattering is observed. Within the planetary boundary layer, an increase of the CH4 mixing ratio, up to a factor of 2, is observed. Different possible interfering factors, such as leakage of the elastic signal and aerosol fluorescence have been taken into consideration. Tests using backscattering from clouds confirmed that the filters in the Raman channel provide sufficient rejection of elastic scattering. The measured methane profiles do not correlate with aerosol backscattering, which corroborates the hypothesis that, in the PBL, not aerosol fluorescence but CH4 is observed. However, the fluorescence contribution cannot be completely excluded and, for future measurements, we plan to install an additional control channel close to 393 nm where no strong Raman lines exist and only fluorescence can be observed.

scholarly journals The Coastal Boundary Layer at the Eastern Margin of the Southeast Pacific (23.4°S, 70.4°W): Cloudiness-Conditioned Climatology

2011 ◽  
Vol 24 (4) ◽  
pp. 1013-1033 ◽  
Author(s):  
Ricardo C. Muñoz ◽  
Rosa A. Zamora ◽  
José A. Rutllant
Keyword(s):  
Boundary Layer ◽  
Lower Troposphere ◽  
Temperature Inversion ◽  
Austral Winter ◽  
Radiative Balance ◽  
Low Level ◽  
Southeast Pacific ◽  
Coastal Margin ◽  
Coastal Boundary Layer ◽  
Coastal Boundary

Abstract A basic climatological description of 29 years of surface and upper-air observations at a coastal site (23.4°S, 70.4°W) in northern Chile is presented. The site is considered to be generally representative of the eastern coastal margin of the southeast Pacific stratocumulus region, which plays an important role in the global radiative balance. The analysis focuses on two of the main elements affecting coastal weather in this region: low-level cloudiness and the state of the subsidence temperature inversion. The objectives of the paper are 1) to present the basic climatological features of these elements and 2) to document the differences in the structure of this coastal boundary layer (BL) associated with the presence or absence of low-level clouds. Low-level clouds (defined here as ceilings less than 1500 m AGL) occur at the site mostly in the night, especially during austral winter and spring. Elevated subsidence inversions show a very large prevalence in the 1200 UTC [0800 local time (LT)] radiosonde profiles analyzed here, with base heights typically between 800 and 1100 m. The seasonal cycle of the subsidence inversion shows an ∼300-m amplitude at inversion base and top and a substantial BL cooling in austral winter. Generally weak and shallow surface-based inversions at 1200 UTC (0800 LT) are present in about 15% of the soundings, with more frequent occurrence in austral fall. The second objective was accomplished by compositing surface meteorology and upper-air profiles conditioned by nighttime low-level cloudiness. More frequent surface inversions in temperature and dewpoint are found for mostly clear nights, as compared to mostly cloudy nighttime conditions. The clear-night BL shows a more stable temperature profile and larger vertical gradients in mixing ratio when compared to the approximately well-mixed cloud-topped BL. Above the BL, the clear composites show a weaker subsidence inversion and more intense northerly winds in the 1000–3000-m layer compared to the cloudy cases. Insights into the physical mechanisms underlying the findings above were sought by comparing the cloudy composites to results of a stationary mixed-layer model of a stratus-capped marine BL, by computing derived parameters pertaining to the temperature budget and the turbulent state of the lower troposphere and by using reanalysis fields to compute regional circulation anomalies associated to coastal low-level cloudiness. The results show physically significant differences in subsidence, horizontal temperature advection, and winds in the lower troposphere associated with the mean clear and cloudy coastal BL. Coastal clear nights appear associated with a cold anomaly in the lower troposphere over the southeast Pacific basin offshore of Peru and Chile, which by thermal wind arguments induce anomalies of southerly winds along the Chilean coast near the surface and northerly winds above the BL, while at the same time reducing the coastal subsidence in the lower troposphere. These results point to the importance of properly representing the sea–land temperature contrast and the topographic impact on the lower-tropospheric flow in order to adequately model the coastal BL mean state over this region.

The Asymptotic Temperature Profile for Forced Convection Turbulent Boundary Layers With and Without Pressure Gradient

2003 ◽  
Author(s):  
Xia Wang ◽  
Luciano Castillo
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Temperature Profile ◽  
Forced Convection ◽  
Boundary Layers ◽  
Power Law ◽  
Equations Of Motion ◽  
Turbulent Boundary Layers ◽  
Similarity Analysis ◽  
Temperature Profiles

Similarity analysis of the equations of motion is used in order to study forced convection turbulent boundary layers with and without pressure gradient. New scalings are found for both the inner and the outer temperature profiles, respectively. It is shown that by normalizing the temperature profiles using the new scalings, the effects from the Pe´clet number and pressure gradient can be removed completely from the profiles. Therefore, the asymptotic solutions can be obtained even at the finite Pe´clet number. Moreover, using the Near-Asymptotic principle, a power law solution is derived for the temperature profile in the overlap region. This power law solution is a consequence of the fact that the boundary layer depends on two different temperature scalings.

scholarly journals Boundary layer temperature measurements of a noctual urban boundary layer

2018 ◽  
Vol 176 ◽  
pp. 06004
Author(s):  
Simon Holloway ◽  
Hugo Ricketts ◽  
Geraint Vaughan
Keyword(s):  
Boundary Layer ◽  
Solid State ◽  
Nd:Yag Laser ◽  
Narrow Band ◽  
Spectral Response ◽  
Urban Boundary Layer ◽  
Temperature Profiles ◽  
Lidar System ◽  
Interference Filters ◽  
Diode Pumped

A low-power lidar system based in Manchester, United Kingdom has been developed to measure temperature profiles in the nocturnal urban boundary layer. The lidar transmitter uses a 355nm diode-pumped solid state Nd:YAG laser and two narrow-band interference filters in the receiver filter out rotational Raman lines that are dependent on temperature. The spectral response of the lidar is calibrated using a monochromator. Temperature profiles measured by the system are calibrated by comparison to co-located radiosondes.

scholarly journals Climatological Description of Seasonal Variations in Lower-Tropospheric Temperature Inversion Layers over the Indochina Peninsula

2006 ◽  
Vol 19 (13) ◽  
pp. 3307-3319 ◽  
Author(s):  
Masato I. Nodzu ◽  
Shin-Ya Ogino ◽  
Yoshihiro Tachibana ◽  
Manabu D. Yamanaka
Keyword(s):  
Seasonal Variations ◽  
Potential Temperature ◽  
Lower Troposphere ◽  
Temperature Inversion ◽  
Static Stability ◽  
Boreal Winter ◽  
Type I ◽  
Tropospheric Temperature ◽  
Malay Peninsula ◽  
Indochina Peninsula

Abstract In this study operational rawinsonde data are used to investigate climatological features of seasonal variations in static stability in order to understand the behavior of temperature inversion layers, that is, extremely stable layers in the lower troposphere over the Indochina Peninsula region, at the southeastern edge of the Asian continent. Static stability was evaluated from the vertical gradient in potential temperature (Δθ/Δz). Stable (Δθ/Δz &gt; 10 K km−1) and unstable (Δθ/Δz &lt; 1 K km−1) layers frequently appear over the Indochina Peninsula region during boreal winter. Temporal and vertical variations in stability during the boreal winter can be categorized into three characteristic types, type I: the mean height of stable layers increases from 2 to 5 km from the dry to the rainy season over inland areas of the Indochina Peninsula and southern China; type II: similar to type I, with the additional occurrence of stable layers at a height of ∼1 km, mainly over coastal areas of the Indochina Peninsula; and type III: stable layers at a height of ∼2 km, mainly over the Malay Peninsula. We did not find any significant seasonal change in the vertical distribution of stable layers over the Malay Peninsula.

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